TWe have completed the characterization of over 20 human genes associated with metastasis. The characterization data is or will be shortly available to CCR investigators under the terms of an intramural MTA mechanism. In addition, we have developed a protocol for reproducible transfecting siRNAs into human breast epithelial cells capable of forming acini in 3D culture. We are now using this model system to screen for siRNAs that induce gross phenotypic changes that may reflect different stages of the metastatic process.